Why do the four Gospels give different accounts of Mary going to the open tomb of Jesus?

A:The actual differences in the four accounts are dealt with in the related question, Who went to the tomb and found that Jesus had risen? The reason for the differences is partly in the lack of detail originally provided in the Gospel of Mark.

Mark's Gospel was the first gospel written, approximately 70 CE. Theologians have long known of a clear literary dependency among the three synoptic gospels. Scholars have demonstrated that this is because the authors of Matthew and Luke relied on Mark for their information about the life and mission of Jesus; for example, Matthew contains some 600 of the 666 verses in Mark, often in exactly the same Words in the English language. John was inspired by Luke, with some material taken direct from Mark. So, the other gospel authors relied substantially on Mark. However, Mark origginally ended at verse 16:8 with the young man telling the women that Jesus was risen and they fled in terror, telling no one. This is an unsatisfactory ending with little to prove that the resurrection was real, and perhaps an anticlimax after the story of the crucifixion

Ian Wilson (Jesus: The Evidence) says that because the Matthew gospel alone tells the story of the guard, the violent earthquake and the 'angel of the Lord' rolling away the entrance stone, it is probably safest to regard these as pious embroideries by an author demonstrably over-fond of the miraculous.

The author of Luke's Gospel seems never to have known about Matthew's Gospel, believed to have been written some ten years earlier, and improved the original account in his own way. The women did not see Mark's young man, but two men, whom Luke stops short of calling angels although leaving us in little doubt that they were angels.

The author of John's Gospel made several improvements on Luke's account, including the involvement of the disciple 'whom Jesus loved'. He seems to have been unwilling to give a woman the honour of being the first to find the tomb empty, so had Mary run back as soon as she saw the stone had been moved, without going into the tomb.

The 'Long Ending' (verses 16:9-20) was added to Mark much later, to provide the necessary evidence that the resurrection was real.